Disk drives are widely used in computers, consumer electronics and data processing systems for storing information in digital form. The disk drive typically includes one or more storage disks and one or more head gimbal assemblies. Each head gimbal assembly includes a suspension and a slider assembly having a slider that transfers information to and from the storage disk. In many disk drives, in order to decrease the likelihood of unwanted contact between the slider assembly and the storage disk, the slider assembly is positioned off the storage disk when the drive is not powered up or when data transmission is not occurring. For example, the slider assembly can be unloaded onto a ramp positioned inward from an inner diameter or beyond an outer diameter of the storage disk, also referred to as “ramp load technology”. Once the disk drive receives a command necessitating the transmission of data, an actuator loads the slider assembly directly over a data storage area of the storage disk.
Because today's disk drives demand a greater amount of data storage, utilizing as much of the disk surface as possible for storing data has become of great importance. However, this desire to use more of the disk surface for data storage must be balanced with concerns of data loss and damage to the storage disk during repositioning of the slider assembly from the ramp to directly over the storage disk. During repositioning of the slider, dings, scratches and/or data loss can occur due to contact between the edges or corners of the slider and the storage disk. Other types of disk contact can result in frictional heating, causing erasure of data, commonly known as soft errors. Further, long term effects can result in premature degradation of the read/write head.
Through experimentation, it has been determined that providing a certain range of pitch static angles and/or roll static angles during loading and/or unloading of the slider assembly relative to the storage disk can be beneficial in reducing the incidence of contact between the slider and the storage disk. As used herein, the pitch static angle is the angle of the air bearing surface of the slider in a substantially longitudinal direction of the slider relative to the storage disk. The roll static angle is the angle of the air bearing surface of the slider in a direction substantially perpendicular to the longitudinal direction of the slider relative to the storage disk.
In conventional disk drives, a pitch torque or roll torque of the slider is often inherently generated as a function of the stiffness of the suspension and the pitch static and/or roll static angle. This type of slider torque can be undesirable during certain drive operations, such as during a seek mode or during data transfer while the slider is flying directly over the disk surface.